does xinerama give you the ability to work a screen seperatly?
and can you not get a metamode like this? : "1024x768,1024x768;1024x768,null" for example
then just by pressing CTRL-ALT-KP_PLUS you'd go single-monitor and can play games on one screen...? (maybe you'd need the randr extension, I'm not sure)
Alien is my name and headbiting is my game.